Solar cells are electrical devices that convert light energy into electrical energy using the photovoltaic (‘PV’) effect. By stringing solar cells together, a PV solar panel can be formed to provide a power generating device. Solar cells are increasingly being used as a backup power supply for various consumer products such as mobile phones and personal digital assistants.
Fabrication of solar cells involves a sequence of processing steps with solar wafers as the raw input material. Typically, pick and place robots are used to transfer solar wafers from their storage magazines to designated conveyers, which then convey the solar wafers to designated processing stations. An example of a processing station is a sorting station where 2D and 3D inspections may be performed on-the-fly by vision inspection modules to provide various measurements of the solar wafers such as wafer geometry, wafer thickness, bow and warp. Based on these measurements, the solar wafers are sorted accordingly and assembled into various storage magazines.
However, conventional pick and place robots employed in fabrication of solar wafers typically require multiple motion axes to ensure that an angular orientation of the solar wafers is maintained throughout the fabrication process. Consequently, in addition to a complex control system to ensure that the pick and place robots function properly, a large footprint is also required to provide sufficient space for operation of the multiple motion axes. Further, such pick and place robots are prone to machine downtime due to the complex construction of their multiple motion axes, which disadvantageously lowers throughput and efficiency. In addition, maintenance of such pick and place robots usually requires specialized skill which increases maintenance costs.
Thus, it is an object of this invention to seek to address the problems of conventional pick and place robots used in the fabrication of solar wafers and solar cells.